Formaldehyde and methylamine reactivity in interstellar ice analogues as a source of molecular complexity at low temperature

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Volume 549 (January 2013)

A&A, 549 (2013) A40

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Table 3

Parameters for thermal reactions, desorptions, and photo-destruction.

Chemical reactions	Reaction rate^a	ν₀ (s^-1)	ν₀(dif) (s^-1)	E (K)	Ref.

H₂CO+NH₃ →NH₂CH₂OH	k₁	0.5 × 10^-2	3.3 × 10^-9	541	(Bossa et al. 2009b)
H₂CO+CH₃NH₂ →CH₃HNCH₂OH	k₂	1.5 × 10^-2	3.3 × 10^-9	133	This work
CO₂+2CH₃NH₂ →CH₃NHCH₃NHCOO⁻	k₁₃	2 × 10^-2	3.3 × 10^-9	445	(Bossa et al. 2009a)

Species	Desorption rate^a	ν₀ (s^-1)	E(K)	Ref.

NH₃	k₅	3 × 10¹²	3008	(Sandford et al. 1993)
H₂CO	k₄	1 × 10¹³	3250	(Theule et al. 2012)
CH₃NH₂	k₈	3 × 10¹²	3008	(c)
NH₂CH₂OH	k₉	3 × 10¹²	6980	(Bossa et al. 2009b)
CH₃HNCH₂OH	k₁₁	3 × 10¹²	6980	(Bossa et al. 2009b)

Species	Photo-destruction rate^b	σ (photon^-1 cm²)		Ref.

CH₃HNCH₂OH	k₁₂	3 × 10^-19		this work
NH₃	k₆	3.2 × 10^-20		(Cottin et al. 2003)
CH₃NH₂	k₇	3.2 × 10^-20		(Cottin et al. 2003)
H₂CO	k₃	1.0 × 10^-19		(Woodall et al. 2007)
NH₂CH₂OH	k₁₀	4.5 × 10^-19		(Duvernay et al. 2010)
CO₂	k₁₄	3.8 × 10^-19		(Cottin et al. 2003)

Notes.

^(a)

The rate coefficients are given in the form k = ν₀exp( − E / T), where T is the ice temperature, ν₀ the pre-exponential factor, and E the activation energy (reaction or desorption). The diffusion factor (ν₀(dif)) is obtained using the method developed by Hasegawa et al. (1992).

^(b)

Photo-destruction rates are written as k = σf, where σ represents the photo-destruction cross-section and f the interstellar ultraviolet radiation field.

^(c)

Since NH and CHNH have the same desorption behaviour in our vacuum conditions, we used the same desorption rate.

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